The present invention relates to a propylene resin composition having excellent anti-scratch characteristic. Specifically, provided is a polyolefin resin composition comprising a high crystalline polypropylene resin, a rubber component, an inorganic filler and an aluminosiloxane masterbatch, with excellent damage resistance such as anti-scratch characteristic thereby giving very low surface damage, excellent heat resistance, good rigidity and impact properties and injection moldability, for car interior or exterior parts.
In car industry, as weight reduction and high performance of plastic materials has been continuously achieved, there has been consistently increasing demand on such plastic materials in various parts of a car. Among various plastic materials, especially the demand on polyolefin material is rapidly increasing as compared with other plastic materials, owing to its low specific gravity and accordingly low weight, easy recycling, relatively low price thereof and the like. Especially among polyolefin resins, polypropylene resin can be variously used in diverse applications, for example, as interior parts of a car such as a panel, door trim, console body, pillar, trim or the like and, as exterior parts such as a bumper, side molding or the like.
However, a polypropylene resin has an inherent limitation in that it is very difficult to obtain balanced properties between excellent flow characteristics and excellent rigidity or impact properties. To overcome said limitation of the material itself, methods for obtaining a resin composition having various characteristics has been being developed, by adjusting the amount of inorganic additives, rubber components and the like being added. Consequently, numerous polypropylene resin compositions became developed and accordingly, it naturally raised further complicating concerns regarding productivity such as molding conditions, molding techniques or the like depending on each product.
In the meantime, resin compositions used in car interior materials have a problem that the surface thereof gets easily damaged or dirty by the hand or shoes of a driver and passengers. In order to prevent such surface damage and discoloration owing to contamination, a pad type instrument panel has been provided in which a polypropylene compound composition or an engineered plastic is used as a core material, and a polyurethane foam and a polyvinylchloride (PVC) or a thermoplastic elastomer (TPE) are used as a surface coating material. However, the above method has some problems such as a requirement of an additional use of polyurethane foam and PVC or TPE for a surface coating material in its production when compared with manufacturing methods for conventional products, an increase in the number of processes leading to an increase in production cost, and an environmental pollution since the resulted products is not recyclable.
For solving these problems, other methods were suggested by replacing the polyurethane foam with a polypropylene having high melt strength, or replacing PVC with TPE to enhance the recycling. However, these methods also had problems of poor adhesion between the foam and the core layer, and increase in process cost.
On the other hand, for solving the above problems, a method has recently been developed to provide a polypropylene resin composition for car interior parts, in which a high isotactic polypropylene is used as a base resin thereby giving maximized rigidity, a reactor-made thermoplastic polyolefin (RTPO) with an increased content of ethylene-propylene rubber during propylene polymerization is used to modify impact properties under the minimized use of rubber, and at the same time, rubbers having various molecular structures such as high density polyethylene resin or styrene-ethylene-butylene-styrene terpolymer (SEBS) are additionally used to improve anti-scratch characteristic. However, when further improvement in anti-scratch characteristic is tried according to said method, an additional use of inorganic materials also increases impact properties, leading to a problem of decrease in flexural modulus.